<html>
<script>

var result = 0;
var count = 0;
for( var a = 3; a <= 99; a = a + 2){
	result = result + a;
	count++;
}

console.log("result: " + result + " count: " + count ); // 2499 49

( 99 - 3 ) / 2 + 1 = 48 + 1 = 49
 
</script>
</html>